A way of saying that a stripper has one big, fat ass without her knowing it. Using the safe assumption that strippers don't know French, they will think that they are being complimented when you are actually stating that they have one big, fat ASS.

Alex: Yo James, isn't that your ex girlfriend on the stage?! She definitely now has one beaucoup booty.

James: Oh snap! That is her! I can't believe she became a stripper. But she definitely had a fat ass when we were dating. Just the way I like it